Safety leg for vehicle lift



United States Patent Ofilice 3,353,724 Patented Jan. 16, 1968 3,363,724 SAFETY LEG FOR VEHICLE LIFT James H. Quatkemeyer, San Bruno, Calif., assignor to J. D. Cochin, Manufacturing Company, South San Francisco, Caiif.

Filed Oct. 5, 1966, Ser. No. 584,555 12 Claims. (Cl. 187-849) ABSTRACT OF THE DISCLOSURE A latch mechanism suitable for use as a safety leg for a vehicle lift wherein a latch member is movable from an operative location extending outwardly from a tube to a retracted position within the tube. Means is provided to hold the latch member in the operative location and to clear the same whereby the latch member can be retracted when the tube is telescoped into a second tube. Means is also provided to bias the latch member toward its operative location when it is retracted.

This invention relates to improvements in latch mechanisms and, more particularly, to a safety device for use with vehicle lifts.

The present invention resides in an elongated, extensible safety leg having an improved latch for holding a vehicle lift in an elevated position in the event of failure of the fluid actuating system of the lift. The safety leg is of the type having a pair of relatively telescoped tubes with the inner tube being movable up and down with the lifting post of the vehicle lift. The inner tube has a pair of upper and lower slots in the side and a latch member pivotally mounted therein adjacent to the lower slot. The latch member may pivot into and out of the lower slot and thereby into and out of its latched position. An elongated unlatching unit extends upwardly from the latch member and is accessible through the upper slot. Thus, the unlatching action can be accomplished even though the latch member is positioned at an inconvenient location below ground level.

Vehicle lifts are generally provided with safety latches to prevent the lift from falling in the even of failure of hydraulic pressure keeping it elevated. Conventional latches comprise inner and outer tubular members with the inner member being slotted and provided with a latch member pivotally mounted at the lower end of the inner tube and movable through the slot for engaging the upper end of the outer tubular member if the lift should start to fall. To unlatch this type of apparatus, an operator must actually touch the latch member either with the hand or foot to move it into the inner tube before the lift can be lowered.

One type of vehicle lift for giving almost complete accessibility to the entire underside of a vehicle utilizes swingable support arms on a U-shaped base carried at the upmr end of the lifting post of the lift. The lift, however, requires a pit for receiving the U-shaped base when the lift is in its retracted or lowered position and this pit is generally about 18 deep. Also, the upper end of the outer tube must be at the bottom of the pit to assure safe operating conditions at all times.

To use a conventional safety latch with this lift, it is necessary for the operator to reach into the pit and unlatch the latch member at the bottom of the pit. This is clearly an inconvenience especially where the adjacent surfaces are dirty and oily. Moreover, the pit has safety doors which swing up and down and cover the lift when it is recessed in the pit. These doors are open when the lift is elevated. The operator would, thus, have to reach over the doors as well as reach into the pit to unlatch the safety mechanism.

The present invention, while being useable for a number of different purposes, is especially adapted for use with the lift of the type described. To this end, it has an actuating control member above the latch member but operably connected thereto for latching and unlatching purposes. In this way, an operator can unlatch the safety device without having to reach into the pit or without having to get into the pit to operate the latch with his foot. The unlatching step is thereby greatly simplified notwithstanding the position of the latch member when the lift is at its highest position. The presentmechanism also provides a latch which is self-operating in that it is biased toward its latched position when it is recessed in the inner tube. Thus, as the lift elevates, the latch member will automatically move into its operative position and become latched to protect against injury to the person or damage to the vehicle or the lift upon any failure of the lifting apparatus.

The latch of this invention is simple and rugged in construction and can be made with a minimum number of parts. Also, an operator needs no special skills to operate the latch.

The primary object of the invention is to provide an extensible safety leg having a latch mechanism which not only moves automatically into its latched condition when the leg is extended but also can be unlatched at a location spaced from the latching zone so that the leg is especially adapted for use with a vehicle lift of the type which is recessed below a working surface when not in use.

A further object of this invention is to provide a vehicle lift having a safety leg of the type described wherein the lift, in its elevated position, is prevented from falling and an operator can readily unlatch the latch member of the leg without reaching into or standing in a pit adapted to receive the lift as would be required with conventional latching mechanisms.

Another object of the invention is to provide a safety leg having latch mechanism of the aforesaid character wherein the swingable latch member of the mechanism is biased toward its latched disposition by the unlatching control member so that the control member serves a dual purpose to thereby avoid the necessity of additional structure to accomplish one of these two functions.

Other objects of the invention will become apparent as the following specifications progress, reference being had to the accompanying drawing wherein in the drawing:

FIG. 1 is an end, elevational view of the latch mechanism with a vehicle lift of the type capable of being recessed in a pit;

FlG. 2 is a view of the mechanism, partly in section, with the latch member in its latched condition; and

FIG. 3 is a view similar to FIG. 2 but illustrating the latch member in its unlatched condition.

Latch mechanism 10 includes a pair of relatively telescoped tubes 12 and 14 which are normally vertically disposed. Tube 14- has a latch member 16 pivotally coupled thereto adjacent its lower end by a shaft 18 disposed transversely of the tube. Latch member 16 has a side edge 20 which converges to a top edge segment 22 to form a projection 24 which is movable into and out of a position extending through a longitudinal slot 26 in tube 14.

Latch member 16 also has a top surface segment 28 coextensive with segment 22 and joined thereto by a shoulder 29. Segment 28 is adapted to be engaged by the lower face 30 of a relatively thick disc 32 rigidly secured to the lower end of a control rod 34. Rod 34 extends longitudinally of tube 14 and has a relatively thin disc 36 at its upper end.

An L-shaped actuating member 38 is pivotally coupled by means of a pin 40 to'tube 14 adjacent to a second slot 42 therein. Member 38 has a pair of spaced arms 3 44 which embrace rod 34 and a leg 46 integral with and being perpendicular to arms 44. Leg 46 fits in slot 4-2 when arms 44 extend transversely of tube 14 as shown in FIG. 2.

A cap 48 closes the upper end of tube 14 and has an internally threaded bore 50 for coupling mechanism 10 to structure above it.

Mechanism it? is suitable for a number of different uses but it is especially adapted for use with a vehicle lift 52 of the type shown in FIG. 1. Lift 52 has a cylinder 5 in which a lifting post 56 reciprocates. Hydraulic fluid is directed by conduit 58 into and out of cylinder 54 for raising and lowering post 56. A U-shaped base 60 is connected to the upper end of post 56 and moves therewith. Base 6% has swingable arms 62 for engaging the underside of a vehicle disposed above the lift.

To accommodate the U-shaped configuration of base 60, a pit 64- is provided in the working surface 65. This pit normally is approximately 18" in depth and is cOvered by a pair of swingable doors 66 when base 69 is in the pit. Doors 66 are hinged for rotation about horizontal axes.

Mechanism it) is shown adjacent to cylinder 54 with base 60 recessed in pit 64. Tube 12 is embedded along with cylinder 54 and is maintained parallel therewith by connecting brackets 67.

The operation of the assembly of FIG. 1 is as follows: As post 56 is raised, tube 14 moves out of tube 1.2 and carries latch member 16 upwardly therewith. As soon as it is aligned with slot 26, latch member ll6 rotates in a counterclockwise sense when viewing FIG. 2 and extension 24 moves through slot 26. This allows disc 32 and thereby rod 34 to descend until face 30 of this disc engages the top edge segment 28 of latch member 16. Shoulder 29 prevents latch member 16 from moving inwardly of tube 14. In this operative position, disc 36 is directly above arms 44 and the latter extend inwardly of tube 14 from pin 40.

in the event that the hydraulic fluid in cylinder 54 were to fail, the lift would descend only to a point at which extension 24 would engage the upper end of tube 5.2. The lift could descend no further since shoulder 29 would engage disc 32. Mechanism would thereby prevent injury to an operator beneath base so and would guard against damage to a vehicle on the lift.

To unlatch mechanism 10 before lowering the lift, the operator manually pulls on leg 46 to cause it to swing outwardly and downwardly. This action forces arm 4-4 against the underside of disc 36, thus, raising it to the dashed line position of FIG. 2. Leg .6 will remain in an outwardly extending position since disc 36 will now rest on the upper ends of arms 44 and there will be no force tending to swing member 38 in a clockwise sense when viewing FIG. 2.

Even though latch member 16 will still extend through :slot 26, it is swingable into member 14 under the influence of tube 12 so long as disc 32 is in the dashed line position .of FIG. 2.

As leg 46 engages the upper end of tube 12, it will :swing inwardly and allow rod 34 to lower. However, seg- :rnent 22 will be across the path of disc 32 so that downward movement of the rod is kept to a minimum. However, disc 32 will engage the inclined segment 22 in the .manner shown in FIG. 3 so as to bias latch member 16 toward its latched position. Thus, on the upstroke the latch member will then move outwardly and through slot 26 as soon as it clears tube 12. The length of rod 34 is such as to place actuating member 33 at a convenient position above or near the top of pit 64. Thus, the operator can easily unlatch mechanism 10 without having to reach into the pit or stand in it. Mechanism it) therefore avoids having to use conventional latches which would require that the unlatching be done manually within the pit.

Latch mechanism 10 has been described with respect to the type of vehicle lift which is recessed in a pit when not in use. Mechanism it) also is adapted equally well for use with the ordinary type of vehicle lift wherein the frame which contacts the underside of the vehicle is positioned at ground level when it is lowered. For use with this type of lift, an operator need only to reach to the location corresponding to the upper slot in the inner tube to unlatch member 16. This upper slot can be placed at a convenient height so that the operator need not bend over or stoop down to any appreciable degree to unlatch member 16.

While several embodiments of this invention have been shown and described, it will be apparent that other adaptations and modifications can be made without departing from the true spirit and scope of the invention.

What is claimed is:

l. A latch mechanism comprising: a pair of relatively telescoped tubes, the inner tube having longitudinally extending slot means therein; a latch member pivotally aounted within the inner tube adjacent one portion of the slot means and being freely movable into and out of an operative location extending partially outwardly from the inner tube through said slot means when said inner tube extends outwardly from the outer tube; an actuating member pivotally mounted in said inner tube adjacent another portion of said slot means and movable into either of a pair of operative positions, said actuating member being accessible through said other portion of said slot means; and means operably coupling said latch and actuating members to cause said latch member to be held in Said operative location when said actuating member is in a first of said posixions and to permit said latch member to be moved into said inner tube by said outer tube when the actuating member is in the second of said positions, whereby the inner tube can be alternately locked in place and be free to move into the outer tube.

2. A latch mechanism as set forth in claim 1, where in said tubes are vertically disposed and said slot means includes a pair of spaced slots, one slot being below the other slot, said coupling means including a rod having a pair of elements at each end, the lower element being engageable with the latch member, said actuating member having an arm for engaging the underside of the upper element for lifting the rod when said actuating member moves to said second position, said arm being disposed to support and thereby hold the upper element in a lifted position when the actuating member is in said second position.

3. A latch mechanism as set forth in claim 1, wherein said actuating member has an arm engageable with said coupling means for holding the latter away from said latch member when said actuating member is in said second position.

4. A latch mechanism as set forth in claim 1, where: in said tubes are vertically disposed and said coupling means includes a rod having a disc at its upper end, said actuating member including an L-shaped unit provided with an arm engageable with the lower face of the disc for lifting the same, there being a leg perpendicular to the arm and movable through said slot means into a position extending laterally from the inner tube after the arm has raised said disc and said rod whereby the disc is supported by the arm and the rod is thereby maintained in an elevated position.

5. A latch mechanism as set forth in claim 1, wherein is included a vehicle lift having a vertically reciprocable U-shaped base, and pit means for receiving the base when the same is in a lowered condition, said outer tube being adjacent to said lift and having its upper end at the bottom of said pit means, said actuating member being spaced above said bottom when said lift is in its highest position.

6. A latch mechanism comprising: a pair of vertically disposed, relatively telescoped tubes, the inner tube having longitudinally extending slot means therein; a latch member pivotally mounted within the inner tube adjacent to one portion of the slot means and movable into an operative location extending partially outwardly therefrom through said slot means when said inner tube extends outwardly from the outer tube, said latch member having a top surface provided with a shoulder; an actuating member pivotally mounted in said inner tube adjacent to another portion of said slot means and movable into either of a pair of operative positions, said actuating member being accessible through said other portion of said slot means; and a rod within the inner tube and movable relative thereto, said rod having a disc on its lower end, said disc being in the path of the shoulder and preventing inward movement of the latch member relative to the inner tube when said actuating member is in a first of said positions, said actuating member being movable to the second of said positions permitting said rod to be elevated to thereby shift said disc out of said path and allow said latch member to move inwardly of the inner member, whereby the inner tube can be alternately locked in place and be free to move into the outer tube.

7. A latch mechanism comprising: a pair of vertically disposed, relatively telescoped tubes, the inner tube having longitudinally extending slot means therein; a latch member pivotally mounted within the inner tube adjacent to one portion of the slot means and movable into an operative location extending partially outwardly therefrom through said slot means when said inner tube extends outwardly from the outer tube, said latch member having a top surface provided with a segment, said segment being inclined when said latch member is in said inner tube; an actuating member pivotally mounted in said inner tube adjacent to another portion of said slot means and movable into either of a pair of operative positions, said actuating member being accessible through said other portion of said slot means; and means including a vertically reciprocal rod coupling said latch and actuating members to cause said latch member to be held in said operative location when said actuating member is in a first of said positions and to permit said latch member to move inwardly of said slot means when the actuating member is in the second of said positions, said rod having a lateral projection at its lower end, said projection being engageable with said segment to bias said latch member out of said inner tube.

8. A latch mechanism comprising: a pair of relatively telescoped tubes, the inner tube having longitudinally extending slot means therein; a latch member mounted in said inner member for free pivotal movement into and out of an operative location extending through one portion of said slot means; means removably blocking the return path of travel of said latch member into said inner member when the latch member is in said operative location; and means accessible through another portion of said slot means and coupled with said blocking means for shifting the latter out of said path, said latch member having a surface engageable with and being transverse to said outer tube when the latch member is in said operative location, whereby the surface will engage and be moved by said outer tube as the inner tube moves thereinto and when said blocking means is out of said path.

9. A latch mechanism as set forth in claim 8 wherein said latch member has a second surface, said blocking means being engageable with said second surface for biasing the latch member toward operative location when the latch member is within the inner tube.

10. A latch mechanism as set forth in claim 8 wherein said shifting means holds said blocking means out of said path until said latch member is disposed in said outer tube.

11. A latch mechanism as set forth in claim 8 wherein said shifting means includes a projection engageable with the outer tube when the inner tube moves thereinto to shift the projection to an operative position permitting said blocking means to move toward said path, said latch member having a surface transversely of the direction of movement of said blocking means and engageable thereby when the blocking means is permitted to return toward said path, whereby the latch member is biased toward said operative location.

12. A latch mechanism comprising: a pair of relatively telescoped tubes, the inner tube having longitudinally extending slot means therein; a latch member mounted in said inner member for movement into and out of an operative location extending through one portion of said slot means; means removably blocking the return path of travel of said latch member into said inner member when the latch member is in said operative location; and means coupled with said blocking means for shifting the latter out of said path to permit the latch member to be moved out of said operative location and into said inner tube, said latch member having a surface extending transversely of the direction of movement of said blocking means, whereby the latch member is biased toward said operative location when said blocking means moves toward said path of travel and engages said surface.

References Cited UNITED STATES PATENTS 2,100,617 11/1937 Thompson 187-8.61 2,684,129 7/1954 Jaseph 187-8.49 2,935,049 5/1960 Krenning 187-849 EVON C. BLUNK, Primary Examiner. H. C. HORNSBY, Assistant Examiner. 

